Exploitation of petroleum waste sludge with local bauxite raw material for producing high-quality refractory ceramics

The aim of this work is to exploit the petroleum waste sludge, through mixing with different quantities of the natural raw bauxite, present in abundance in Al zubierah area in Saudi Arabia, to manufacture high-quality refractory ceramics for use at high temperature applications. Seven batches were prepared using different weight proportions of local bauxite and petroleum waste sludge (100-0 wt%), (80-20wt%), (60-40 wt%), (50-50 wt%), (40-60 wt%), (20-80 wt%) and (0-100 wt%), respectively referred to Ml, M2, M3, M4, M5, M6 and M7, the samples were prepared through solid-state technique to form cylindrical bodies by means of hydraulic pressing. The prepared bodies were dried and fired at different temperatures up to 1600 degrees C. The chemical and mineralogical compositions of raw bauxite and petroleum waste sludge were investigated using X-ray fluorescence (XRF) and X-ray diffraction (XRD) techniques. Their microstructure was depicted using scanning electron microscope (SEM) attached with energy dispersive X-ray unit (SEM + EDAX). The various technological properties of the ceramics bodies fired at different temperature (800-1600 degrees C) were tested. These properties involve; sintering parameters (bulk density and apparent porosity) tested using kerosene displacement method, the linear change tested by measuring the dimension shrinkage, mechanical properties (cold crushing strength) tested using an automatic compression machine as well as the refractory properties; permanent linear change, thermal shock resistance, refractoriness (Segar cone test) and load- bearing capacity. All tests were carried according to the international standard specifications. The chemical analysis using (XRF), and mineralogical investigation using (XRD), confirm that the petroleum waste sludge composed mainly from barite mineral (BaSO4), kaolinite (Al-2(Si2O5(OH)(4)) and quartz (SiO2) while raw bauxite composed mainly from bohmite (AlO(OH)), gibbsite (Al(OH)(3)) and kaolinite. According to the International Standards, the used bauxite belongs to the high-quality bauxite grade (HQB). The firing temperature affects differently on the shape of the prepared bodies i.e., while the ceramics bodies prepared from M1-M5 keep their forms even at 1600 degrees C those of M6 and M7 have been fused at only 1400 degrees C. The technological properties of the prepared ceramic bodies are influenced by both firing temperature and the content of petroleum waste sludge. Ceramic bodies of M3 batch composed of 60 wt% of bauxite and 40 wt% of petroleum waste sludge was considered as the optimum among the investigated samples since they satisfy the requirement of the International Standards of refractory ceramics. This work is doubly valuable since it uses an available and cheap raw bauxite and consumes petroleum waste sludge (decreasing air pollution) to produce high-quality refractory ceramics with economic impact.